Memorandum by the Institute of Food Research
The Institute of Food Research (IFR) welcomes
the Government's recent infectious disease strategy, Getting
Ahead of the Curve. IFR is a BBSRC-sponsored Institute with
a major research portfolio in Food Safety Science. The following
comments are made from the perspective of microbiological food
safety and exclude consideration of non-food-borne disease. The
questions are those listed in the Call for Evidence.
1. What are the main problems facing the
surveillance, treatment and prevention of human infectious disease
in the United Kingdom?
The prevention of food-borne disease is not
a static problem, on account of factors such as pathogen evolution,
changes in agricultural production methods, food processing regimes,
demographic factors and consumer habits. A range of initiativeslong-term,
short-term and contingencyare necessary, some of which
will interface directly with industry and with consumers, whilst
others will be directed towards the fundamental biology of food-borne
pathogens and host responses. Maintaining a perspective on the
whole production and consumption chain ("from fork to farm"),
rather than dealing with individual steps or processes in isolation,
is essential. An effective and co-ordinated national skill base
in surveillance, epidemiology and diagnostic microbiology remains
The following are in general medium- and longer-term
issues that in our view must be addressed to provide the underpinning
knowledge essential to effective prevention and control of food-borne
(i) Recognising the organisms that are
the causes of food-borne disease. In a substantial proportion
of food-poisoning outbreaks, the organisms responsible are not
unequivocally identified; therefore the source of the outbreak
and the mode of transmission remain uncertain. Our understanding
of the contribution made to outbreaks by less well-publicised
pathogens (eg Clostridium perfringens; foodborne viral
agents) remains incomplete whilst in other organisms, for example
Campylobacter spp, the characteristics that distinguish
virulent and non-virulent strains still remain poorly defined.
More importantly, the emergence of new pathogens may not be immediately
recognised. More resources devoted to surveillance and microbiological
identification will help to address these issues.
(ii) Understanding the factors that
cause, or prevent, the proliferation of food-borne pathogens.
Substantial progress has been made in the development and
application of mathematical modelling techniques to predict microbial
growth in a range of food environments. Our own work at IFR has
been at the forefront of these developments. This work and its
industrial application are particularly important in the light
of increasing sales and consumption of minimally processed, chilled
foods, prepared without the use of traditional processing methods
such as canning or freezing.
Predictive microbiology must continue to be
underpinned by studies of fundamental physiologyboth at
the level of the single organism (eg to understand the control
of spore germination) and also at the population level (eg to
understand the basis of the quorum-sensing mechanisms that determine
responses to population density). The transmission of food-borne
pathogens depends critically upon their survival in the face of
environmental stresses (eg desiccation; heat/cold shock) and stresses
within the host (eg stomach acid). Such responses are still very
imperfectly understood, particularly in relatively poorly characterised
organisms such as Campylobacter spp. Finally, it is important
to understand the processes that drive the selection and emergence
of variant individuals in response to environmental factorsvariants
that may, for example, be unusually resistant to normal food preparation
or preservation regimes or that may display altered virulence
(iii) Understanding host-pathogen interactions.
There has been enormous progress in understanding the molecular
mechanisms by which (some) bacterial pathogens can survive and
proliferate in an animal or human host and cause disease. This
has been facilitated by the development of techniques to study
gene function at the level of the single bacterial cell, leading
(in particular) to the identification of genes (eg in Salmonella
spp) that are critical to the successful invasion of host
cells. In addition, it is particularly important to understand
gastrointestinal and immunological factors that determine whether
or not disease will develop, and the variation of these factors
between individuals and between population groups. Maintenance
and/or manipulation of the native flora of the gastrointestinal
tract may provide an effective means to exclude colonisation by
pathogens and may assist in the prevention of other diseases,
such as colon cancer. Analogously, in pigs and poultry, colonisation
of the gastrointestinal tract by food pathogenic bacteria may
be prevented by "competitive exclusion" with non-harmful
organisms. This can provide a non-antibiotic-based strategy to
reduce the burden of food-borne pathogens at slaughter.
(iv) Information provision and education.
Good practices depend upon awareness and training provided or
promoted by the education sector, industry, and learned societies
and professional bodies. Balanced and accessible information provision
to consumers is vital, both to promote safe practices in food
preparation and consumption and to ensure that consumers gain
an authoritative, objective assessment of food-associated risks,
including in those cases (notably the BSE episode) where scientific
evidence may at the time be insufficient to provide an accurate
and informed estimate of risk. The agri-food industry is critically
dependent upon consumer confidence and upon national and international
reputation and this requires the establishment of a climate of
There are important issues to be considered
in ensuring that information that is received and understood by
its target audience is actually effective in modifying behaviour.
The notified incidence of food poisoning has increased significantly
in recent years. Although consumer concern about microbiological
food hazards is relatively high, protective behaviour is low,
since in general people believe that they as individuals are at
low risk from food poisoning (particularly from food prepared
in the home). Work at IFR and elsewhere has shown that public
perception of food poisoning is prone to optimistic bias,
in which people believe that they are less at risk from a hazard
than comparable other people. Optimistic bias may adversely affect
risk communication and may impact on the success of public health
campaigns aimed at increasing self-protective behaviour. It has
been argued that such campaigns are unsuccessful because they
fail to change the perception of personal invulnerability.
Thus, whilst people may rate a hazard as more risky generally
following such a campaign, they may not change their rating of
personal susceptibility. It has been shown that there is
a disparity between food safety knowledge and self-reported practices,
in that people are aware of self-protective behaviours, but nevertheless
do not use safe food handling practices.
2. Will these problems be adequately addressed
by the Government's recent infectious disease strategy, Getting
Ahead of the Curve?
"Getting Ahead of the Curve"
sets out important new recommendations to identify and deal with
the threats posed by infectious disease, including recommendations
on education and information provision, and proposes a rationalised
management structure for microbiology laboratories undertaking
diagnosis, profiling and surveillance work. The document does
not, however, present a review of current staffing and other resources,
and whether these will in future be adequate. The relationships
between the proposed National Infection Control and Health Protection
Agency and the Food Standards Agency (which will retain responsibility
for food safety) are not defined in the document, but we assume
that suitable arrangements for joint working will be put in place.
We presume that there will be mechanisms to ensure a concerted
approach to research on infectious diseases that will not only
involve the new Agency and MRC but also FSA, BBSRC and other relevant
3. Is the United Kingdom benefiting from
advances in surveillance and diagnostic technologies: if not,
what are the obstacles to its doing so?
As pointed out in "Getting Ahead of
the Curve", the UK has a strong competence in surveillance
and in the application of new technologies in this area. Both
traditional microbiological skills and new genomic and "phenomic"
profiling techniques are necessary; reliance on too narrow a skill
base (even if modern) is potentially dangerous.
4. Should the United Kingdom make greater
use of vaccines to combat infection and what problems exist for
developing new, more effective or safer vaccines?
Most food-borne diseases in the UK are not a
priority for the development of vaccines for humans. On the other
hand, organisms used as food (food plants and lactic acid bacteria)
can provide in principle promising vehicles for the delivery of
oral vaccines against other infectious diseases.
It may be economic to develop and employ vaccines
against common food-borne pathogens, such as Campylobacter,
in food-animal hosts (cf. also comment on "competitive
exclusion" of food-borne pathogens in 1. iii above).
5. Which infectious diseases pose the biggest
threats in the foreseeable future?
Food-borne diseases impose a major health and
economic burden on the UK, though for many of those affected the
consequences are short-lived. The emergence of new food-borne
pathogens is an ever-present threat and there is also the possibility
of the emergence of new and more virulent strains of already-known
food-borne pathogens; since several new or more virulent pathogens
have emerged in the last few decades, it is not unlikely that
more may arise in the future. We would emphasise particularly
the importance of minimising the use of antibiotics in food production
in preventing the emergence of antibiotic-resistant strains.
Food-borne pathogens are potentially agents
for use by bioterrorists.
6. What policy interventions would have the
greatest impact on preventing outbreaks of and damage caused by
infectious disease in the United Kingdom?
This is difficult to judge, since as indicated
above, an effective prevention policy requires the orchestration
of a variety of complementary functions and initiativessurveillance,
diagnosis, research, education and training, and information provision.
Import controls and immigration procedures have
an obvious and vital role to play in controlling the import of
potentially infective materials, such as meat and meat products
that may harbour new pathogen strains (including antibiotic-resistant
strains). This may become an even more important issue with the
enlargement of the European Union.
We hope that these comments will be useful to
the Sub-Committee in considering the Government's Report and the
future strategies for the surveillance and prevention of infectious
disease. Please do not hesitate to get in touch if we can be of
Dr Nick Walton